The present invention relates to a novel driving device consisting of a stator and an armature in which the armature is moved along a plane by an electric current, and a two-dimensional precise positioning device making use of the driving device for use in a semiconductor manufacturing apparatus.
In the past, it has been common to use a precise positioning device in a semiconductor manufacturing apparatus which comprises a finely displacable loading table. Prior art methods for driving the loading table involve the use of a step motor or a rotary type D.C. servo motor the rotational motion being converted into a linear motion by means of a feed screw or the like. However, in view of the mechanical structure of these devices it is difficult to give a microfine movement of 1 micron or less to a loading table, and if it is intended to obtain a high resolution, generally the moving speed is slow due to the fact that the pitch of the screw becomes fine. Consequently, in most examples the loading table was formed with a double structure in which a microfine displacement was separately provided, and so the device was mechanically complex and expensive. On the other hand, recent development of D.C. linear motors has advanced and excellent results have been obtained achieving high resolution of 1 micron or less and high speed movement. However, both the method depending upon feeding of a screw and the method employing a linear motor can provide only a linear motion to the loading table. In general there are many cases where the loading table must achieve a two-dimensional motion along a plane. Thus, it has been common practice to construct an X-Y orthogonal coordinate system by making use of linear driving sources which are orthogonal to each other and providing guide rails for restraining movements in the directions other than the driving directions.